1. Field of the Invention
The present invention relates to a slide stroke adjusting device equipped to minimize the vibration in the rotation system of a press machine.
2. Description of the Related Art
A conventional device for adjusting the stroke of a slide for a press machine is disclosed in Japanese laid-open Utility Model Publication 7-26099.
Referring now to FIGS. 4A and 4B, showing a large end of a connecting rod 11 of a press machine (not shown). A small end of connecting rod 11 is connected with a slide of the press machine (not shown).
A liner 11A is affixed on the inside of the large end part of connecting rod 11. An eccentric bushing 2 is slidably and rotatably connected through liner 11A to connecting rod 11. An eccentric part 1A, of an eccentric shaft 1, connects and joins by an interference fit to eccentric bushing 2. A groove 5 is provided on one side of eccentric bushing 2. Groove 5 receives a fixing rod 6 movable in parallel with the axial direction of eccentric shaft 1. In other words, groove 5 and fixing rod 6 act as a fixing means to fix eccentric bushing 2 relative to connecting rod 11.
An internal gear and a hub 3 are positioned on eccentric bushing 2 opposite groove 5. Internal gear is affixed to eccentric bushing 2. Hub 3 is movable in an axial direction about eccentric shaft 1. A teeth space 7A, is formed on the outer perimeter surface of hub 3. Teeth space 7A meshes with inner teeth (not shown) of internal gear 7. Further, a collar 9 formed on eccentric shaft 1. Collar 9 acts to restrict the movement o hub 3 away from internal gear 7 and eccentric bushing 2.
A coupling body 10 is movable in the axial direction of eccentric shaft 1, away from hub 3. Coupling body 10 contacts and pushes the side surface of hub 3, to mesh the teeth (not shown) formed on the outer perimeter surface of hub 3, with the inner teeth (not show n) of internal gear 7.
An oil passage 4, through eccentric shaft 1 helps release the interference fit of eccentric part 1A with eccentric bushing 2. Pressurized oil, provided through oil passage 4 to an opening (not shown), contacts the inner surface of eccentric bushing 2. A packing 2A and a packing 2B are formed about the outer perimeter surface of eccentric part 1A where eccentric part 1A joins eccentric bushing 2. Under some conventional constructions, packing 2A and packing 2B are omitted.
A packing 3A and 3B are positioned on the inner perimeter surfaces of hub 3 where hub 3 contacts the outer perimeters of eccentric part 1A and eccentric shaft 1. An oil passage 8, is formed through eccentric shaft 1 to a surface of eccentric part 1A opposite hub 3. Oil passage 8 allows the passage of pressurized oil to urge hub 3 outward away from eccentric part 1A.
During stroke adjustment operations, fixing rod 6 is placed in groove 5, to fix the rotation of eccentric bushing 2. Pressurized oil next passes through oil passage 8. Hub 3 moves outward from eccentric part 1A toward collar 9. As a result, hub 3 no longer meshes with internal gear 7. Pressurized oil then passes through oil passage 4. Eccentric bushing 2 is partially elastically deformed. As a result, the interference fit of eccentric part 1A is released, and eccentric shaft 1 rotates to adjust the amount of eccentricity relative to eccentric bushing 2.
Referring to FIG. 4B, the top-dead center position places an eccentricity P, of eccentric part 1A with respect to eccentric shaft 1, in the position shown. The top-dead center position further places an eccentricity Q, of eccentric bushing 2 with respect to eccentric part 1A, in the position shown. Thus, a maximum stroke length is 2xc3x97(P+Q). Further, a minimum stroke length is 2xc3x97(Qxe2x88x92P).
After stroke adjustment, pressurized oil in oil passage 4 and oil passage 8 is released. The shape of eccentric bushing 2 is elastically reformed. The interference fit with eccentric part 1A re-engages. Coupling body 10 presses against hub 3 and meshes the outer perimeter teeth of hub 3 to the inner teeth of internal gear 7. Fixing rod 6 is withdrawn from groove 5, and coupling body 10 is withdrawn from hub 3 and placed on standby in a non-interfering area.
Using the described stroke adjustment process, the stroke of connecting rod 11 is adjusted. The stroke adjustment conforms to the pitch of the inner teeth of internal gear 7. Contact provided by meshing internal gear 7 with hub 3, transfers torque from eccentric part 1A to eccentric bushing 2. Torque is then transferred from eccentric bushing 2 to connecting rod 11.
Negative results arise when using the above type of conventional stroke adjustment. Under rapid stroke rate, or an increasing stroke rate, the multiple eccentric members rotate rapidly. Thus, internal centrifugal and centripetal forces result in vibration, heat, wear, shorter equipment life span, and increased maintenance costs and operation down-time.
It is an object of the invention to provide a stroke adjustment device for a press machine.
It is another object of the invention to provide a stroke adjustment device that minimizes the unbalance and vibration resulting from the rotation of conventional stroke adjusting devices.
It is another object of the invention to provide a stroke adjustment device that is adaptable to vary stroke adjustment positions.
It is another object of the present invention to provide a stroke adjustment device that both minimizes vibration from a press machine and adjusts simultaneously to stroke adjustments of the press machine.
It is another object of the present invention to provide a stroke adjustment device that is adaptable to a range of rotary systems requiring stroke adjustment and vibratory dampening.
Briefly stated, the present invention relates to a stroke adjusting device for removing instability in a mechanical rotation system. The stroke adjusting device includes an adjustable rotation balancing weight attached to an eccentric bushing positioned about an eccentric shaft. The adjustable rotation balancing weight contains a weight portion adaptable to counteract the instability of the eccentric mechanical rotation system thus minimizing vibration. A hydraulic system enables simple adjustment of the stroke adjusting device.
According to an embodiment of the present invention, there is provided a stroke adjusting rotation balancing device, comprising: an eccentric shaft portion, the eccentric shaft portion receiving a vibration from an external mechanical system, a rotation balancing eccentric bushing affixed about a first part of the eccentric shaft portion, a rotation balancing weight adjustably joined to the eccentric bushing, means for fixing the rotation balancing weight relative to the eccentric bushing, and means for adjusting the rotation balancing weight relative to the eccentric bushing and the eccentric shaft whereby the rotation balancing weight counteracts and dampens the vibration from the external mechanical system.
According to an embodiment of the present invention, there is provided a stroke adjusting and rotation balancing device, wherein: the means for adjusting includes a hydraulic circuit, and the hydraulic circuit supplying a hydraulic pressure to the eccentric bushing and the rotation balancing weight thereby allowing adjustment of the rotation balancing weight relative to the eccentric bushing to dampen the vibration.
According to an embodiment of the present invention, there is provided a stroke adjusting and rotation balancing device, wherein: the means for fixing includes a groove, the groove formed in the rotating balancing weight, the means for fixing further includes a fixing rod, the fixing rod extending from a fixed external position, and the fixing rod formed to fit into the groove, whereby the rotation balancing weight is prevented from rotation relative to the eccentric bushing thereby allowing adjustment of the rotation balancing weight relative to the eccentric bushing to dampen the vibration.
According to an embodiment of the present invention, there is provided a rotation balancing device for a press machine, comprising: a connecting rod having a large end, an eccentric bushing slidably and rotatably provided inside the large end, an eccentric shaft having a first and second side, an eccentric part formed on a first side of the eccentric shaft, the eccentric part adjustably fittable inside the eccentric bushing, the eccentric shaft receiving vibration during operation of the press machine, a rotation balancing eccentric bushing, the rotation balancing eccentric bushing affixed to a second side of the eccentric shaft, a rotation balancing weight, the rotation balancing weight adjustably joined to the rotation balancing eccentric bushing and formed to minimize vibration during operation of the press machine, means for fixing the rotation balancing weight during adjustment, and means for adjusting the rotation balancing weight relative to the rotation balancing eccentric bushing and the eccentric bushing relative to the eccentric part thereby minimizing vibration during operation of the press machine.
According to an embodiment of the present invention, there is provided a rotation balancing device for a press machine, wherein: the means for fixing includes a fixing rod affixed to an external member, the means for fixing includes a groove formed in the rotation balancing weight, and the fixing rod engagable with the groove during adjustment of the rotation balancing device thereby preventing rotation of the rotation balancing weight relative to the external member.
According to an embodiment of the present invention, there is provided a rotation balancing device for a press machine, wherein: the means for adjusting includes a first and a second hydraulic circuit, the first hydraulic circuit providing adjustment of the eccentric part relative to the eccentric bushing, the second hydraulic circuit providing adjustment of the rotation balancing eccentric bushing relative to the rotation balancing weight, and the first and second hydraulic circuits being supplied simultaneously whereby adjustment of the eccentric part and the rotation balancing eccentric bushing occur simultaneously.
According to an embodiment of the present invention there is provided a stroke adjusting device in a rotary system including a connecting rod, an eccentric bushing slidably and rotatably provided inside a first end of the connecting rod, and an eccentric shaft in which an eccentric part is joined to the eccentric bushing by an adjustable fit, the stroke adjusting device comprising: a rotation balancing eccentric bushing affixed to the eccentric shaft, a rotation balancing weight fitted to the rotation balancing eccentric bushing, the rotation balancing weight adjustable relative to the rotation balancing eccentric bushing, means for fixing the rotation balancing weight during adjustment, and a hydraulic circuit enabling the adjustment of the rotation balancing weight relative to the rotation balancing eccentric bushing whereby vibration is minimized in the rotary system.
According to an embodiment of the present invention there is provided a stroke adjusting device, wherein: the hydraulic circuit enables simultaneous adjustment of the eccentric part relative to the eccentric bushing and the rotation balancing weight relative to the rotation balancing eccentric bushing.
According to an embodiment of the present invention there is provided a stroke adjusting device, wherein: the means for fixing includes a groove portion formed on the rotation balancing weight, and a fixing rod member affixed to an external member and insertable into the groove portion to restrain rotation of the rotation balancing weight relative the eccentric shaft.
Furthermore, when conducting the operation of stroke adjustment, the interference fit of the eccentric part and the eccentric bushing is released. In the present embodiment, in addition to the interference fit of the eccentric part and the eccentric bushing, the interference fit of the rotation balancing eccentric bushing and the rotation balancing weight is release-able and adjustable. Thus, when the eccentric shaft is rotated in order to adjust the stroke, together with the rotation of the eccentric part, the rotation balancing eccentric bushing is also rotated, and the eccentricity of the rotation balancing weight changes and vibration is damped.
As a result, the eccentricity of the rotation balancing weight can be changed according to the change in eccentricity of the eccentric bushing. Therefore, regardless of the various stroke amounts, the vibration or unbalance in the rotation system may always be minimized.
In the invention according to the present embodiment, the oil pressure circuit that releases the interference fit of the eccentric bushing and the eccentric part and the oil pressure circuit that releases the interference fit of the rotation balancing eccentric bushing and the rotation balancing weight operate in common. As a result, adjustment is simplified and the time consumed in the adjustment procedure is minimized thereby minimizing costs.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.